ActionScript 3.0 :: Disable Click Event When Object Is Hidden?

I have a game where "targets" hide behind trees and when they pop out from behind, you click them and they are destroyed. For some reason though, when you click the tree they are hiding behind, they still get destroyed. I want them to be safe from the user clicks when hiding. Here is a sample of the code I am using:

Code:

stage.addEventListener(MouseEvent.CLICK, onClickHandler, false, 0, true);
function onClickHandler(event:MouseEvent):void
{

[code]....

I tried adding an else if statement like so:

Code:

else if(bullet.hitTestObject(backtrees)) {
poof.x = bullet.x;
poof.y = bullet.y;

[code]....

but that did nothing as well. As you can see, it is not the click of the user that causes the target to disappear, but the hittestobject that causes it to disappear.